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WL1801MOD: Unable to connect to a particular access point on a particular channel

Simon Werner1
Prodigy 40 points
Part Number: WL1801MOD
Other Parts Discussed in Thread: WL1801

We have a WL1801MOD wi-fi module and using wpa_supplicant to connect to a TP-Link router.  When change the router to only provide channel 11, the connection will become extremely unstable, and eventually stop altogether.  The behaviour after a fresh reboot is that a few connection errors occur, but the final one `4WAY_HANDSHAKE_TIMEOUT` repeats.  The connection is fine on all the other channels.  Many other devices (including a BeagleBone Blue with similar TI Wi-Fi module) can connect on this channel to the router.

We are running the latest firmware.

We have tried different variant of wpa_supplicant, including v2.9-r8.8 as provided by TI.  The command we use for testing is `wpa_supplicant -Dnl80211 -iwlan1 -c/etc/wpa_supplicant.conf -d`.

The system logs are here:

[   23.557466] wlan1: authenticate with 3c:84:6a:6f:12:12
[   23.567814] wlan1: send auth to 3c:84:6a:6f:12:12 (try 1/3)
[   25.141837] wlan1: send auth to 3c:84:6a:6f:12:12 (try 2/3)
[   25.622712] wlan1: send auth to 3c:84:6a:6f:12:12 (try 3/3)
[   27.141840] wlan1: authentication with 3c:84:6a:6f:12:12 timed out
[   29.618899] wlan1: authenticate with 3c:84:6a:6f:12:12
[   29.632977] wlan1: send auth to 3c:84:6a:6f:12:12 (try 1/3)
[   31.087389] wlan1: send auth to 3c:84:6a:6f:12:12 (try 2/3)
[   31.683703] wlan1: send auth to 3c:84:6a:6f:12:12 (try 3/3)
[   33.135153] wlan1: authentication with 3c:84:6a:6f:12:12 timed out
[   35.939893] wlan1: authenticate with 3c:84:6a:6f:12:12
[   35.950630] wlan1: send auth to 3c:84:6a:6f:12:12 (try 1/3)
[   36.719364] wlan1: authenticated
[   36.732166] wlan1: associate with 3c:84:6a:6f:12:12 (try 1/3)
[   38.101966] wlan1: associate with 3c:84:6a:6f:12:12 (try 2/3)
[   38.801764] wlan1: associate with 3c:84:6a:6f:12:12 (try 3/3)
[   39.042216] wlan1: RX AssocResp from 3c:84:6a:6f:12:12 (capab=0xc11 status=0 aid=1)
[   39.062201] wlan1: associated
[   41.081838] wlcore: WARNING Unable to flush all TX buffers, timed out (timeout 500 ms
[   41.096370] wlcore: Association completed.
[   47.754314] wlan1: deauthenticated from 3c:84:6a:6f:12:12 (Reason: 6=CLASS2_FRAME_FROM_NONAUTH_STA)
[   47.847563] wlan1: authenticate with 3c:84:6a:6f:12:12
[   47.857530] wlan1: send auth to 3c:84:6a:6f:12:12 (try 1/3)
[   49.109515] wlan1: send auth to 3c:84:6a:6f:12:12 (try 2/3)
[   49.912626] wlan1: send auth to 3c:84:6a:6f:12:12 (try 3/3)
[   51.141830] wlan1: authentication with 3c:84:6a:6f:12:12 timed out
[   54.154159] wlan1: authenticate with 3c:84:6a:6f:12:12
[   54.164224] wlan1: send auth to 3c:84:6a:6f:12:12 (try 1/3)
[   55.141864] wlan1: send auth to 3c:84:6a:6f:12:12 (try 2/3)
[   56.072932] wlan1: send auth to 3c:84:6a:6f:12:12 (try 3/3)
[   56.213861] wlan1: authentication with 3c:84:6a:6f:12:12 timed out
[   58.815324] wlan1: authenticate with 3c:84:6a:6f:12:12
[   58.826453] wlan1: send auth to 3c:84:6a:6f:12:12 (try 1/3)
[   60.101980] wlan1: send auth to 3c:84:6a:6f:12:12 (try 2/3)
[   60.879309] wlan1: send auth to 3c:84:6a:6f:12:12 (try 3/3)
[   62.101849] wlan1: authentication with 3c:84:6a:6f:12:12 timed out
[   72.997397] wlan1: authenticate with 3c:84:6a:6f:12:12
[   73.007072] wlan1: send auth to 3c:84:6a:6f:12:12 (try 1/3)
[   73.869403] wlan1: authenticated
[   73.882173] wlan1: associate with 3c:84:6a:6f:12:12 (try 1/3)
[   74.291375] wlan1: RX AssocResp from 3c:84:6a:6f:12:12 (capab=0xc11 status=0 aid=1)
[   74.315868] wlan1: associated
[   75.521937] wlcore: WARNING Unable to flush all TX buffers, timed out (timeout 500 ms
[   75.540082] wlcore: Association completed.
[   78.006983] wlan1: deauthenticated from 3c:84:6a:6f:12:12 (Reason: 15=4WAY_HANDSHAKE_TIMEOUT)
[   79.980469] wlan1: authenticate with 3c:84:6a:6f:12:12
[   79.989551] wlan1: send auth to 3c:84:6a:6f:12:12 (try 1/3)
[   81.141848] wlan1: send auth to 3c:84:6a:6f:12:12 (try 2/3)
[   81.541639] wlan1: authenticated
[   81.561849] wlan1: associate with 3c:84:6a:6f:12:12 (try 1/3)
[   83.106824] wlan1: associate with 3c:84:6a:6f:12:12 (try 2/3)
[   83.614583] wlan1: associate with 3c:84:6a:6f:12:12 (try 3/3)
[   85.141867] wlan1: association with 3c:84:6a:6f:12:12 timed out
[   87.547426] wlan1: authenticate with 3c:84:6a:6f:12:12
[   87.580102] wlan1: send auth to 3c:84:6a:6f:12:12 (try 1/3)
[   89.141834] wlan1: send auth to 3c:84:6a:6f:12:12 (try 2/3)
[   89.651930] wlan1: send auth to 3c:84:6a:6f:12:12 (try 3/3)
[   89.941839] wlan1: authentication with 3c:84:6a:6f:12:12 timed out

And the wpa_supplicant log:

CHAN-11-not-working.log

  • 0
    TI__Mastermind 35795 points

    Hi,

    - Is this issue specific to one device or can it be reproduced on multiple devices ?

    - Was RF validated on all channels using PLT tool ?

    - Was WiLink8 module configured - https://www.ti.com/lit/ug/swru561a/swru561a.pdf ( section 4 ) ?

    Best

    Saurabh

  • 0 in reply to S
    Prodigy 40 points
    S said:
    Is this issue specific to one device or can it be reproduced on multiple devices ?

    I could reproduce it on one other device, although another device worked fine.

    S said:
    Was RF validated on all channels using PLT tool ?

    I checked the RF, but only when actively connected, not using the PLT tool (since it takes a bit to set up). Attached are spectrograms of two units, a "GOOD" one and a "BAD" one.  Both on channel 11.  The "BAD" unit shows that the spectrum is not clearly defined.  Note that the other channels on the "BAD" unit are fine, it's only channel 11 that looks like this.  See the attached screenshots.

    Bad wifi module on channel 11:

    BAD module on Channel 11

    Good wifi module on channel 11:

    GOOD module on Channel 11

    The Bad wifi module on channel 10 - all looks good.

    S said:
    Was WiLink8 module configured - https://www.ti.com/lit/ug/swru561a/swru561a.pdf ( section 4 ) ?

    Yes

  • 0 in reply to Simon Werner1
    TI__Mastermind 35795 points

    Hi,

    It doesn't seem to be a  s/w issue since same s/w is running on both 'good' and 'bad' devices

    Is this a custom device or are you running on an EVM  ?

    Are there any other radios running on this device ?

    Best

    Saurabh

  • 0 in reply to S
    Prodigy 40 points
    S said:
    Is this a custom device or are you running on an EVM  ?

    This is our own board.

    S said:
    Are there any other radios running on this device ?

    We retested with other RF transmitters disabled and the problem is the same.

    Further testing shows that the WL1801 module has strange spectral behaviour for all "good" and "bad" modules.  The bad module just exhibits is worse.  Note again that this is against a TPLink router, we investigated this because a customer was the issue on their TPLink router.

    Below is the spectrum of a "bad" device with only wlan1 (which is used to access the router, wlan0 is disabled).  The yellow is against a Ruckus router, as you can see it's clean and what we expect.  The purple is all over the place.  The device is unable to connect to the router.

     

    Below is the spectrum of a "good" device in the same setup as before. The yellow line is the same as above, but the purple line shows that there are still some strange spectral things going on. The device is able to connect to the router.

     

  • 0 in reply to Simon Werner1
    TI__Mastermind 35795 points

    Hi,

    Our modules are certified as per regulatory standards : https://www.ti.com/tool/WL18XX-CERTIFICATION

    Since you don't see this issue on beaglebone blue, it  could be specific to your hardware .

    I will share this query with h/w experts . We will get back to you on this.

    Saurabh

  • 0 in reply to S
    TI__Mastermind 34570 points

    Hi Simon,

    You can request a design review here.

    BR,

    Seong